Podarkeopsis chinensis, Tong & Yang & Qiu & Ke & Wang, 2023

Tong, Shan, Yang, Deyuan, Qiu, Jian-Wen, Ke, Caihuan & Wang, Zhi, 2023, Podarkeopsis chinensis sp. nov. (Annelida, Hesionidae) from southeastern China, ZooKeys 1173, pp. 339-355 : 339

publication ID	https://dx.doi.org/10.3897/zookeys.1173.106112
publication LSID	lsid:zoobank.org:pub:4F949981-76B5-4758-8D41-012D55D46529
persistent identifier	https://treatment.plazi.org/id/E34C0784-0B1E-4EE7-AF72-06F612CC5BCA
taxon LSID	lsid:zoobank.org:act:E34C0784-0B1E-4EE7-AF72-06F612CC5BCA
treatment provided by	ZooKeys by Pensoft
scientific name	Podarkeopsis chinensis
status	sp. nov.

Treatment

Podarkeopsis chinensis sp. nov.

Figs 1 View Figure 1 , 2 View Figure 2 , 3 View Figure 3 , 4 View Figure 4 , 5 View Figure 5

Materials examined.

Holotype: China; Guangdong, Daya Bay, Guishan Island ; 22°49'4"N, 114°47'11"E; 1 April 2021; Deyuan Yang, Zhi Wang leg.; intertidal zone; XMU-Pol-2021-105, the anterior fragment with 21 chaetigers, length: 3.4 mm, width without parapodia: 0.6 mm GoogleMaps . Paratypes: China ; Guangdong, Daya Bay , Guishan Island ; 22°49'4"N, 114°47'11"E; 1 April 2021; Deyuan Yang , Zhi Wang leg.; intertidal zone; paratype 1 (XMU-Pol-2021-106), the anterior fragment with 16 chaetigers, length: 3.4 mm, width without parapodia: 0.6 mm. China ; Guangdong, Daya Bay ; 22°41'2"N, 114°37'17"E / 5.6 m; 13 March 2021; Zhi Wang, Lizhe Cai, Kang Mei, Xiaoyu Zhao leg.; shallow subtidal muddy sediment; paratype 2 (MBM287621), the anterior fragment with 15 chaetigers, length: 3.0 mm, width without parapodia: 0.6 mm; paratype 3 (XMU-Pol-2021-197), the anterior fragment with 13 chaetigers, length: 2.0 mm, width without parapodia: 0.6 mm. CHINA; Fujian, ZhaoAn Bay ; 23°43'14"N, 117°17'22"E / 2.6 m depth; 28 May 2021; Zhi Wang, Yuyao Li leg.; shallow subtidal hard muddy sediment; paratype 4 (XMU-Pol-2021-201), the anterior fragment with 11 chaetigers, length: 1.7 mm, width without parapodia: 0.6 mm; paratype 5 (XMU-Pol-2021-203), the anterior fragment with 10 chaetigers, length: 1.4 mm, width without parapodia: 0.6 mm; paratype 6 (XMU-Pol-2021-204), the anterior fragment with 14 chaetigers, length: 2.8 mm, width without parapodia: 0.7 mm. China; Fujian, ZhaoAn Bay ; 23°42'30"N, 117°18'36"E / 2.6 m depth; 28 May 2021; Zhi Wang, Yuyao Li leg.; shallow subtidal hard muddy sediment; paratype 7 (XMU-Pol-2021-205), the anterior fragment with 15 chaetigers, length: 3.2 mm, width without parapodia: 0.6 mm; paratype 8 (XMU-Pol-2021-207), the anterior fragment with 14 chaetigers, length: 2.9 mm, width without parapodia: 0.6 mm; paratype 9 (XMU-Pol-2021-208), the anterior fragment with 14 chaetigers, length: 2.1 mm, width without parapodia: 0.7 mm; paratype 10 (XMU-Pol-2021-209), the anterior fragment with 16 chaetigers, length: 3.0 mm, width without parapodia: 0.6 mm. China; Fujian, ZhaoAn Bay; 23°43'11"N, 117°18'11"E / 3.5 m depth; 28 May 2021; Zhi Wang, Yuyao Li leg.; shallow subtidal hard muddy sediment; paratype 11 (XMU-Pol-2021-213), the anterior fragment with 21 chaetigers, length: 3.5 mm, width without parapodia: 0.6 mm; paratype 12 (XMU-Pol-2021-214), the anterior fragment with 21 chaetigers, length: 3.9 mm, width without parapodia: 0.6 mm; paratype 13 (XMU-Pol-2021-215), the anterior fragment with 14 chaetigers, length: 3.1 mm, width without parapodia: 0.7 mm; paratype 14 (MBM287622), the anterior fragment with 2 chaetigers, length: 0.9 mm, width without parapodia: 0.5 mm. China; Fujian, ZhaoAn Bay; 23°42'34"N, 117°20'12"E / 2.4 m depth; 28 May 2021; Zhi Wang, Yuyao Li leg.; shallow subtidal hard muddy sediment; paratype 15 (XMU-Pol-2021-221), the anterior fragment with 10 chaetigers, length: 1.5 mm, width without parapodia: 0.6 mm; paratype 16 (XMU-Pol-2021-223), the anterior fragment with 9 chaetigers, length: 1.4 mm, width without parapodia: 0.6 mm; paratype 17 (XMU-Pol-2021-224), the anterior fragment with 10 chaetigers, length: 1.5 mm, width without parapodia: 0.6 mm GoogleMaps .

Diagnosis.

Two pairs of eyes arranged in a trapezoid shape. Palps one pair, biarticulated, palpostyle as long as the palpophore. Double aciculae in both notopodia and neuropodia. Notopodial furcate chaetae present, base of the shorter tine smooth.

Description

(based on holotype, unless otherwise stated). Anterior fragment with 1-21 chaetigers. Body cylindrical. Fixed specimens uniformly pale (Fig. 2A, B View Figure 2 ).

Prostomium twice as wide as long. Eyes two pairs, placed towards the posterior prostomial margin, trapezoidally arranged, anterior pair kidney-shaped, larger than posterior pair, posterior pair oval (Fig. 2A, B View Figure 2 ). Palps one pair, biarticulated, palpostyle as long as palpophore. Three antennae, tapered. Median antenna thinner than lateral ones, lost in holotype, about half the length of lateral ones in paratype 5 (Fig. 2A, C, D View Figure 2 ). Nuchal organs of paratype 5 on lateral-posterior edge of prostomium (Fig. 2E, F View Figure 2 ). Pharynx strong, reversible, anterior edge with 10 triangular papillae (Fig. 2A, B, G View Figure 2 ). Teeth, minute, one pair, nearly triangular, symmetrically distributed on the inner wall of pharynx, visible from anterior view of pharynx in both holotype and paratypes (Fig. 2H-L View Figure 2 ). Tentacular cirri eight pairs, biarticulated, most cirrostyles missing (Fig. 2A, B View Figure 2 ).

Parapodia sesquiramous with acicula in cirrophore and without protruding notopodial chaetae in chaetigers 1-3 (Fig. 3A-C View Figure 3 ), biramous thereafter (Fig. 3D-I View Figure 3 ). Notopodial aciculae one pair, extending into cirrophores in chaetigers 1-4, extending into a small notopodial lobe in following chaetigers (Fig. 3A-I View Figure 3 ). Notopodial cirri digitate, about twice the length of neuropodial lobe, neuropodial cirri thinner, not longer than neuropodial lobe (Fig. 3C, E-G, J View Figure 3 ). Neuropodial aciculae one pair, neuropodial lobe in anterior chaetigers developed, prechaetal lobe long, digitated, postchaetal lobe rounded (Fig. 3A-F View Figure 3 ).

Notochaetae 3 types. Furcate chaetae 2 or 3, bifid, base of the shorter tine smooth, longer tine about 2.3 times as long as shorter one (Fig. 4A-D View Figure 4 ). Acicular chaetae blunt, 1 or 2 (Fig. 4A, C, D View Figure 4 ). Capillary chaetae smooth and slender, longer than furcate chaetae and acicular chaetae, 1 or 2 in number (Fig. 4A, C, D View Figure 4 ). Neurochaetae all composite falcigers (Fig. 4E-H View Figure 4 ). Blade of all falcigers unidentate, blade length/width ratios ranging from 7 to 80 (Fig. 4F-H View Figure 4 ). Hooded neurochaetae rarely present, 0 or 1 per parapodia; if present, in subacicular bundle of neurochaetae (Fig. 4F2, H2 View Figure 4 ).

Intraspecific variation.

Examination of the holotype and several paratypes of P. chinensis sp. nov. revealed different numbers of the three kinds of notochaetae. In the holotype, there were 2 or 3 furcate chaetae, 1 or 2 acicular chaetae, and 1 or 2 capillary chaetae. However, several paratypes had 2-4 furcate chaetae, 1-4 acicular chaetae, and 1-3 capillary chaetae. The number of these chaetae may be related to the developmental stages or environmental conditions.

Remarks.

The new species can be distinguished from the other nine species of the genus in having 1) median antenna about half as long as lateral ones, while P. arenicolus , P. brevipalpa , P. galangaui , P. glabrus , and P. helgolandicus have median antenna shorter than half of the lateral ones ( Hartmann-Schröder 1959; Hartman 1961; Laubier 1961; Hilbig and Dittmer 1979; Rizzo and Salazar-Vallejo 2014); another species, P. perkinsi , however, has median antenna about two-thirds as long as lateral one ( Hilbig 1992); 2) ventral cirri as long as, or barely shorter than neuropodial lobe, while P. brevipalpa , P. galangaui , and P. glabrus have ventral cirri apparently longer than neuropodial lobe ( Hartmann-Schröder 1959; Hartman 1961; Laubier 1961), P. guadalupensis and P. levifuscina have ventral cirri markedly shorter than neuropodial lobe ( Amoureux 1985; Perkins 1984); 3) double aciculae in both notopodia and neuropodia, while P. capensis , P. glabrus , and P. perkinsi have one aciculae in both notopodia and neuropodia ( Day 1963; Hartman 1961; Hilbig 1992), and P. levifuscina has one acicula in notopodia and double aciculae in neuropodia ( Perkins 1984); and 4) notopodial furcate chaetae with both handles smooth, while P. galangaui , P. glabrus , P. guadalupensis , P. helgolandicus , and P. perkinsi have notopodial furcate chaetae with denticulated at the base of either the shorter handle or both handles ( Hartman 1961; Laubier 1961; Hilbig and Dittmer 1979; Amoureux 1985; Hilbig 1992).

Etymology.

The specific name chinensis is an adjective in the nominative singular, derived from China, where the specimens were collected. The suggested formal Chinese name for this species is “中国健足虫”.

Habitat.

Intertidal, shallow subtidal muddy sediment.

Distribution.

Podarkeopsis chinensis sp. nov. is currently known from Daya Bay, Guangdong and ZhaoAn Bay, Fujian, China. It is expected that this species is widely distributed along the coast of southeast China.